The invention relates to a battery box for storing a battery to be mounted on a vehicle.
A battery to be mounted on a vehicle is stored in an engine room. As shown in the patent document 1, in a van type of vehicle, sometimes, the battery is also stored in such portion of a rear floor as exists near the lower front portion thereof. In both cases, the battery must be disposed and structured so as to be protected against rainwater, mud splash and the like.
In the case that the battery is disposed in the engine room of a vehicle of a type that an engine is mounted on the front portion thereof, a battery installation portion is often disposed in front of or in rear of a tire house of front wheels. This position is sufficiently distant from a road and is hard to suffer directly from rainwater, mud splash and the like. Therefore, as the installation portion, there is employed a tray the rising portion of the outer peripheral edge of which is short.
In the case that the battery is disposed on the rear floor, as in the patent documents 1 and 2, an open window is formed in a floor panel and the battery is mounted onto the rear floor. In this case, there must be employed a structure which can prevent water or the like from invading into the vehicle through the open window. In order to reduce such portion of the battery as projects toward a vehicle room, the battery is installed in such a manner that a portion thereof exists lower than the floor panel.
In the patent document 1, the rear floor is constituted of an upper panel and a lower panel, while a battery box having flanges is mounted on a mounting hole formed in the lower panel. A battery stored in the battery box is held down toward the lower panel by an exclusive holder to thereby bring the flanges of the battery box into engagement with the lower panel. Also, the upper panel has a battery hole formed above the battery box and a lid is mounted on the battery hole with a packing between them.
In the patent document 2, a tray is mounted over two cross members respectively disposed on the lower surface of the floor panel and, on this tray, there is placed a box-shaped battery cover for storing a battery. This battery cover is formed higher than the upper surface of the battery. The battery is fixed to the tray by a battery band or the like mounted through penetration holes respectively formed in the front and rear walls of the battery cover. A service hole is formed in the floor panel situated above the battery, and a lid is mounted on this service hole with a seal member between them. In the patent document 2, the tray protects the battery from water and mud splashed by front wheels, while the battery cover protects the battery from water and mud splashed by rear wheels.
However, in the patent document 1, the flange of the battery box and lower panel are only contacted with each other but are not perfectly sealed. This battery box constitutes a portion of a structure for holding a spare tire mounted under a vehicle body and, therefore, when force for pushing up the spare tire is strong, there is a possibility that clearances can be produced between the flanges of the battery box and lower panel. Also, in the patent document 2, the battery cover includes, in its front and rear walls, a hole for passing a battery band and a hole for passing a cable which are used to hold the battery. Therefore, when water or mud is splashed from the side portions of the tray, such water or mud is easy to invade into the battery cover from the holes formed in the front and rear walls of the battery cover.
In both of the battery box of the patent document 1 and the battery cover of the patent document 2, a sufficient space must be secured under the rear floor. In the case that an opening is formed in the floor panel, the strength of the floor panel is lowered accordingly and, therefore, the area of the opening must be reduced as much as possible. In order to store the battery in a small area, preferably, the battery box may have a simple structure and a clearance between the battery and it may be small. In the case that the battery box is molded using resin, it can also be produced to the shape of the battery. However, when the strength and assembling operation thereof are taken into consideration, it is lower in cost to employ a press-formed product of a metal plate.
In the case that a box-shaped battery box is produced by press molding, it is molded by deep drawing and, therefore, it is restricted by the limit drawing that is allowed in the corner portion of the battery box. That is, in order to store the battery in the battery box in such a manner that the corners of the battery do not interfere with the corner portions of the battery box, there is necessary such battery box that has a larger clearance in the whole periphery thereof at least than the smallest radius of curvature in the limit drawing of material used with respect to the outer shape of the battery. This increases the size of the opening of the floor panel that is prepared in order to mount this battery box.    [Patent Document 1] JP 8-10029 U    [Patent Document 2] JP 2007-45281 A